Poxvirus Expression System Using Native Promoter Integration
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Solution Overview
Problem
Traditional recombinant poxvirus expression systems face limitations such as genetic instability, disruption of neighboring gene expression, and sub-optimal growth properties due to the insertion of promoters, which can affect the immunogenicity and stability of recombinant viruses.
Innovation Solution
A method is developed to insert a nucleic acid sequence encoding a foreign peptide into a poxvirus genome by identifying a poxvirus open reading frame with an initial ATG start codon, placing the sequence downstream of a poxvirus promoter, and ensuring translation initiation at the same position relative to the promoter, allowing expression without inserting a promoter in tandem with the sequence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a promoter is inserted in tandem with the nucleic acid sequence encoding the foreign peptide, then the foreign peptide can be expressed, but the transcription pattern is disrupted and genetic instability increases
Solution Approach 1:
The invention merges the foreign peptide coding sequence with the native poxvirus open reading frame by inserting the foreign sequence immediately after the initial ATG start codon. This integration allows the foreign peptide to be expressed under the control of the native promoter without requiring a separate promoter insertion, thereby maintaining transcriptional integrity and genetic stability while achieving foreign peptide expression.
2Adaptability or versatility
If multiple transgenes are inserted using traditional methods, then more foreign peptides can be expressed, but the choice of promoters and insertion sites is limited and genetic instability increases
Solution Approach 1:
The invention segments the foreign peptide coding sequence into modular units that can be independently inserted after the initial ATG start codon of different poxvirus open reading frames. This modular approach allows multiple foreign peptides to be expressed by targeting different genomic loci, each with its own native promoter, thereby expanding transgene capacity while maintaining genetic stability through the use of stable native promoters.
3Ease of manufacture
If the nucleic acid sequence is inserted at a position that maintains the same ATG start codon position, then translation initiation is optimized, but the insertion position is constrained
Solution Approach 1:
The invention utilizes the native ATG start codon of the poxvirus open reading frame as the initiation site for translation of the foreign peptide. By positioning the foreign peptide coding sequence immediately after this existing start codon, the system leverages the cell's existing translation machinery and regulatory elements, optimizing translation initiation without requiring additional complex regulatory sequences or constrained insertion positioning.
Data Source
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AI summary
There is provided a method for inserting a nucleic acid sequence that encodes a foreign peptide into a poxvirus genome, said method comprising: identifying in the poxvirus genome a poxvirus open reading frame wherein said open reading frame is characterised by an initial ATG start codon and wherein expression of said open reading frame is driven by an operably-linked poxvirus promoter located upstream of the open reading frame and wherein expression of said open reading frame provides a peptide that is non-essential to viability of the poxvirus; and inserting the nucleic acid sequence that encodes the foreign peptide at a position downstream of the poxvirus promoter; wherein following said insertion, (i) the nucleic acid that encodes the foreign peptide is operably-linked to the poxvirus promoter and expression of said nucleic acid is driven by said poxvirus promoter; and (ii) translation of the foreign peptide is initiated at an ATG start codon located at the same position as the ATG start codon of the poxvirus open reading frame. Also provided are a poxvirus vector and corresponding uses of the poxvirus vector in medicine.